Transmission Scheduling of Periodic Real-Time Traffic in IEEE 802.15.4e TSCH-Based Industrial Mesh Networks

Abstract

Time-slotted channel hopping (TSCH) is a part of an emerging IEEE 802.15.4e standard to enable deterministic low-power mesh networking, which offers high reliability and low latency for wireless industrial applications. Nonetheless, the standard only provides a framework, but it does not mandate a specific scheduling mechanism for time and frequency slot allocation. This paper focuses on a centralized scheme to schedule multiple concurrent periodic real-time flows in TSCH networks with mesh topology. In our scheme, each flow is assigned a dynamic priority based on its deadline and the hops remaining to reach the destination. A maximum matching algorithm is utilized to find conflict-free links, which provides more chances to transfer high-priority flows at each time slot. Frequency allocation is implemented by graph coloring to make finally selected links interference free. Simulation results show that our algorithm clearly outperforms the existing algorithms on the deadline satisfaction ratio with a similar radio duty cycle.